Developing the evidence in landscape ecology

Much of the work of the Landscape Ecology group is based on the principle of functional connectivity (that species movement is affected by patch size, isolation and the landscape features between patches). Our current research into how the landscape features between patches affect species movement forms three strands:

This research is used to support forest planning and validate our landscape modelling. Here we present an example from each strand.

Monitoring species movement: Small pearl-bordered fritillary

A small pearl-bordered fritillary butterfly,
Boloria selene

Suitable butterfly habitat within Clocaenog Forest, Wales (in the foreground), with a dense conifer stand in the background, believed to be a barrier to butterfly movement

For eight years 2001 – 2008, the occurrence and numbers of the small pearl-bordered fritillary Boloria selene has been monitored in Clocaenog Forest in north Wales. In collaboration with Butterfly Conservation, we have been able to show that the species acts as a meta-population, where patches can become unpopulated and then be recolonised over time. In 2002, mark-release-recapture experiments were carried out. Of the 321 butterflies marked, only seven were recaptured in a different patch from their mark patch. These travelled up to 3 km across the forest, it is believed they use open and riparian areas and avoid dense mature conifer stands, but we do not know the exact route taken by each butterfly.

We are comparing these few movements, plus the rates at which empty patches get recolonised, with various 'scores' for the permeability of the different forest stands, open spaces and rides along possible movement routes.

Landscape genetics: Wood crickets

The wood cricket Nemobius sylvestris was the subject of a PhD by Niels Brouwers, in collaboration with Bournemouth University. Niels’ work suggested that wood crickets were a woodland edge species and unlikely to cross fields, water or roads. In 2007, in collaboration with the genetic conservation group we caught over 1000 wood crickets in different woodlands on the Isle of Wight, along with samples from three populations on the mainland. We have analysed 15 microsatellite markers to see how related the populations were within and between woodlands. We are now exploring the relationship between genetic similarity and the distance between populations, taking in to account alternative permeability values for the intervening landscape.

Systematic review and meta-analysis

Systematic review is a tool used to collate, summarise, appraise and communicate the results and implications of a large quantity of research and information. It can support decision-making by providing an independent and objective assessment of evidence. In collaboration with the Centre for Evidence Based Conservation at Bangor University, we looked at the evidence that matrix features affect species movement.

We included 315 articles and reports in our review. We used a statistical technique called meta-analysis to combine the results from different studies and look at the variation in the outcomes of the studies.

The pattern that emerged from all the (frequently conflicting) evidence is that matrix features that are more similar to the breeding habitat of a species will tend to increase species movement. However, there is lots of variability and this seems to be down to species behaviour.

Relatively mobile groups like butterflies, birds and large herbivores seem to benefit from increased connectivity. For these species, spatial targeting of measures to create corridors and a matrix with structural similarity to the “home” habitat should enhance population persistence and may promote longer distance movement. However, there was a large number of species for which no information was available.